1. Field of the Invention
The present invention relates to apparatus for injecting particulated material into a hollow enclosure and in particular to a manually operated gun for injecting particulated or comminuted insulation material into a confined wall space.
2. Description of the Prior Art
Because of the rapidly rising costs of energy, the incentives to conserve energy are increasing, especially for domestic users. The potential for energy conservation in the home is substantial because of the amount of energy required to operate home heating and cooling systems. Significant energy loss is substained in older dwellings because of heat gain and heat loss by conduction of thermal energy through uninsulated walls.
A well known and efficient method for insulating wall spaces, such as the wall spaces defined by the studding, inner lathing and outer sheathing of frame buildings, is carried out by filling the spaces with an insulating material conveyed in an air stream. Insulating materials such as mineral or rock wool in granular form are now used extensively as an insulating medium in building construction and particularly in older buildings which require insulation, because such materials may be readily blown into the spaces in old walls and into other remote places by suitable equipment developed for that purpose. Non-mineral insulating materials such as shredded cellulose products also may be injected in the same manner. All of these materials belong to a class of "loose fill" insulating materials such as granulated rock wool, granulated mineral fiber wools, glass fiber materials, cellulose fiber materials, expanded mica, etc.
This so called "loose fill" insulating material is usually packed under compaction in bags or bails. The containers are opened and the material is dumped into a hopper for feeding into an air line for delivery to the area to be insulated. The material is very light in weight, being composed of low density nodules which have been somewhat compressed in the package. The individual nodules should be separated from one another and allowed to expand to full size before placement in a wall. The very nature of the material makes feeding difficult, and the material is very susceptible to compression and compaction, making uniform distribution of the insulation throughout the wall space very difficult to achieve. This results in loss of bulk for filling and an increase in density in the insulated area, leading to increased costs for material and reduction in dead air space in the wall. Further, delivery of the particulated insulation in an air stream is a continuous process which will cause a large amount of insulation material to be wasted by the escape of fugitive particles as the delivery conduit is moved from place to place.
Delivery of insulation by entraining the particulated insulation material in an air stream is typically a commercial operation which is relatively expensive unless carried out on a large scale such as for attic installations. In certain situations, a home owner may desire to insulate a number of wall spaces in a dwelling for which the conventional forced air insulation blowing technique cannot be justified economically or because the wall spaces cannot be reached by the conventional forced air equipment.